.ac-device{background:url(../images/phone.png) no-repeat;width:294px;height:618px;margin:0 auto;position:relative;background-size:294px 618px;-webkit-transition:all 0.3s ease;-moz-transition:all 0.3s ease;transition:all 0.3s ease;-webkit-transform-style:preserve-3d;-moz-transform-style:preserve-3d;transform-style:preserve-3d;}